Improved microbiological procedure for determining erythromycin in milk and some milk products. 1980

C P Harpster, and S E Katz

An improved microbiological assay for erythromycin in milk and some milk products was developed. Acidification of the samples to pH 4.5 resulted in precipitation of milk solids which were separated by centrifugation. The pH of the aqueous supernatant solution was readjusted to pH 8.0 to obtain maximum sensitivity. Th sample cleanup and the use of a single, thin, seeded agar layer with Microsoccus lutea as the assay organism permitted the mesurement of 0.05 micrograms/mL milk with recoveries averaging 84.0%, 0.50 micrograms/g nonfat dry milk with recoveries averaging 55.4%, 0.10 micrograms/g cream cheese with recoveries averaging 100.2%, and 0.05 micrograms/mL buttermilk with recoveries averaging 44.0%. The improved procedures showed superior recoveries and improved the ability to detect and measure lower levels when compared with commonly recommended assay procedures for erythromycin residues.

UI MeSH Term Description Entries
D008837 Micrococcus A genus of gram-positive, spherical bacteria found in soils and fresh water, and frequently on the skin of man and other animals.
D008892 Milk The off-white liquid secreted by the mammary glands of humans and other mammals. It contains proteins, sugar, lipids, vitamins, and minerals. Cow Milk,Cow's Milk,Milk, Cow,Milk, Cow's
D002417 Cattle Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor. Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D003611 Dairy Products Raw and processed or manufactured milk and milk-derived products. These are usually from cows (bovine) but are also from goats, sheep, reindeer, and water buffalo. Dairy Product,Product, Dairy,Products, Dairy
D004917 Erythromycin A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. Erycette,Erymax,Erythromycin A,Erythromycin C,Erythromycin Lactate,Erythromycin Phosphate,Ilotycin,T-Stat,Lactate, Erythromycin,Phosphate, Erythromycin,T Stat,TStat
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001681 Biological Assay A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc. Bioassay,Assay, Biological,Assays, Biological,Biologic Assay,Biologic Assays,Assay, Biologic,Assays, Biologic,Bioassays,Biological Assays

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